Displaying similar documents to “On the class of some projective varieties.”

On the k-regularity of some proyective manifolds.

Alberto Alzati, Gian Mario Besana (1998)

Collectanea Mathematica

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The conjecture on the (degree-codimension + 1) - regularity of projective varieties is proved for smooth linearly normal polarized varieties (X,L) with L very ample, for low values of Delta(X,L) = degree-codimension-1. Results concerning the projective normality of some classes of special varieties including scrolls over curves of genus 2 and quadric fibrations over elliptic curves, are proved.

Algebraic Legendrian varieties

Jarosław Buczyński

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Real Legendrian subvarieties are classical objects of differential geometry and classical mechanics and they have been studied since antiquity (see [Arn74], [Sła91] and references therein). However, complex Legendrian subvarieties are much more rigid and have more exceptional properties. The most remarkable case is the Legendrian subvarieties of projective space; prior to the author's research only few smooth examples of these were known (see [Bry82], [LM07]). Strong restrictions on...

Higher order duality and toric embeddings

Alicia Dickenstein, Sandra Di Rocco, Ragni Piene (2014)

Annales de l’institut Fourier

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The notion of higher order dual varieties of a projective variety, introduced by Piene in 1983, is a natural generalization of the classical notion of projective duality. In this paper we study higher order dual varieties of projective toric embeddings. We express the degree of the second dual variety of a 2-jet spanned embedding of a smooth toric threefold in geometric and combinatorial terms, and we classify those whose second dual variety has dimension less than expected. We also...

On projective degenerations of Veronese spaces

Edoardo Ballico (1996)

Banach Center Publications

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Here we give several examples of projective degenerations of subvarieties of ℙ t . The more important case considered here is the d-ple Veronese embedding of ℙ n ; we will show how to degenerate it to the union of d n n-dimensional linear subspaces of ℙ t ; t : = ( n + d ) / ( n ! d ! ) - 1 and the union of scrolls. Other cases considered in this paper are essentially projective bundles over important varieties. The key tool for the degenerations is a general method due to Moishezon. We will give elsewhere several applications to...